CD74HCT166EE4 Equivalent & Substitute Parts

Part Overview

The CD74HCT166EE4 is a HIGH SPEED CMOS LOGIC 8-bit parallel-in/serial-out shift register manufactured by Texas Instruments. This component functions as a 1-element, 8-bit shift register capable of parallel or serial to serial conversion, housed in a 16-PDIP through-hole package. The device is currently in active product status with 950 pieces available in new original inventory.

Substitute parts are necessary when the primary manufacturer part becomes unavailable, when alternative sourcing is required for supply chain optimization, or when inventory constraints necessitate equivalent component selection. Substitutes must maintain identical electrical specifications, mechanical compatibility, and functional performance to ensure direct replacement capability without circuit redesign.

Substiute Parts

CD74HCT166EE4

Texas InstrumentsIn Stock: 998CD74HCT166EE4 Datasheet

Current PartRFQ

CD74HCT166E

Harris CorporationIn Stock: 2151CD74HCT166E Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution eligibility for the CD74HCT166EE4 is determined by strict equivalence across the following critical parameters:

Electrical Compatibility Requirements:

• Logic Type: Shift Register (1 element, 8-bit configuration)
• Function: Parallel or Serial to Serial conversion capability
• Output Type: Push-Pull
• Supply Voltage Range: 4.5V ~ 5.5V
• Operating Temperature Range: -55°C ~ 125°C

Mechanical Compatibility Requirements:

• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)
• Supplier Device Package: 16-PDIP

Series Compatibility:

• 74HCT series logic family

The CD74HCT166E qualifies as a parametric equivalent based on complete alignment with all electrical and mechanical parameters listed above. Differences in manufacturer origin and product status do not affect functional interchangeability when all specified parameters match.

Parameter Comparison

Engineering Selection Recommendations

Primary Selection: CD74HCT166EE4 (Texas Instruments)

The CD74HCT166EE4 is the recommended primary choice for new designs and procurement. This part maintains active product status, ensuring long-term availability and manufacturer support. The component is ROHS3 compliant, meeting current environmental and regulatory requirements for commercial and industrial applications. Current inventory of 950 pieces supports immediate deployment.

Secondary Selection: CD74HCT166E (Harris Corporation)

The CD74HCT166E is electrically and mechanically equivalent to the primary part and functions as a direct substitute when CD74HCT166EE4 availability is constrained. However, this part carries obsolete product status, indicating discontinued manufacturing and limited future availability. The component is RoHS non-compliant, which may restrict use in applications subject to environmental regulations or customer specifications requiring RoHS certification. Current inventory of 2100 pieces provides temporary sourcing capability. Selection of this substitute should be limited to applications where regulatory compliance is not mandated and where long-term supply continuity is not critical.

Frequently Asked Questions (FAQ)

Q: Can CD74HCT166E be used as a direct replacement for CD74HCT166EE4 in existing circuits?

A: Yes. The CD74HCT166E is electrically and mechanically equivalent. All critical parameters—logic type, bit configuration, function, supply voltage, operating temperature range, output type, and package dimensions—are identical. Direct substitution is functionally valid without circuit modification.

Q: What is the difference between these two parts?

A: The primary differences are manufacturer origin (Texas Instruments vs. Harris Corporation), product status (Active vs. Obsolete), and RoHS compliance (ROHS3 Compliant vs. RoHS non-compliant). Electrical and mechanical specifications are identical.

Q: Should I use CD74HCT166E for new designs?

A: No. For new designs, CD74HCT166EE4 is the appropriate selection. The CD74HCT166E is obsolete, meaning Harris Corporation no longer manufactures this part. Using an obsolete component in new designs creates supply chain risk and may violate customer or regulatory requirements for RoHS compliance.

Q: Are there any package or pinout differences between these parts?

A: No. Both parts use identical 16-PDIP packaging with 0.300" (7.62mm) spacing. Pinout and mechanical dimensions are identical, enabling direct socket substitution.

Q: What does "RoHS non-compliant" mean for the CD74HCT166E?

A: RoHS non-compliance indicates the component may contain restricted substances such as lead, cadmium, or hexavalent chromium. Applications subject to RoHS regulations (EU Directive 2011/65/EU or equivalent) cannot use this part. The CD74HCT166EE4 is ROHS3 compliant and suitable for regulated applications.

Q: Can I mix CD74HCT166EE4 and CD74HCT166E in the same circuit board?

A: Yes. Both parts are electrically and mechanically equivalent. However, mixing components from different manufacturers and compliance statuses may complicate supply chain documentation and traceability. Standardization on a single part number is recommended for production consistency.

Q: What is the 74HCT series?

A: The 74HCT series is a family of high-speed CMOS logic components operating at 4.5V to 5.5V supply voltage. The "HCT" designation indicates compatibility with TTL logic levels while maintaining CMOS power efficiency. Both substitute parts belong to this series.